This invention relates to determining the level of sound occurring at a point in an area of interest; a plurality of such sound level determinations can be used to prepare a sound level contour map for the area of interest. A prior art method of determining the sound level at a plurality of points within an area of interest has consisted of locating a predetermined point within the area of interest by measuring from a known point with a tape measure, measuring wheel or similar device and then recording the sound level sensed by a sound level meter or acoustic monitoring device at that predetermined location. Alternatively, an approximate location can be determined by using a plot plan and visual reference points associated with that plot plan. The prior art worker then measured again to determine the next predetermined point at which the sound level was to be measured. This process was repeated for many points located within the area of interest. However, this prior art method requires laborious and tedious effort on the part of the individual making the measurements which often results in diminished accuracy in the results of the survey. This foregoing method is generally used to obtain the sound level information at a plurality of points in the area of interest to create a sound level contour map. In the event that the objective is to obtain the location of the areas that exceed a certain level of sound, another method is employed which consists of having an individual walk around the area under test while observing the output of a sound level meter. When a point is reached at which the level of sound is equal to or greater than the predetermined limit, the worker then determines that location as discussed hereinabove. This latter method has the same shortcomings that the former method has, that is, it is time consuming and prone to inaccuracies.
Therefore, it is an object of the present invention to provide a method of and apparatus for expeditiously and accurately determining the level of sound occurring at a point in an area of interest.